In U.S. Pat. No. 5,059,166 by Fischell et al is described a radioisotope stent for the treatment of arterial stenoses. In clinical trials, this radioactive stent has been shown to decrease neointimal hyperplasia within the stent but in some patients an "edge effect" has been observed. The edge effect is characterized by a short length of stenosis that appears just proximal or just distal to the edge of the stent. When the edge effect is severe, the blood flow in that artery can be severely diminished.
In U.S. Pat. No. 5,879,282, Fischell et al describe a variety of balloon angioplasty catheter systems each having an inflatable balloon that includes an elastic radioactive section for catheter based radiation of an arterial stenosis. However, this Fischell patent does not consider using such an expandable radioactive source for delivering a radioactive stent to eliminate a vascular blockage such as an arterial stenosis. Moreover, in U.S. Pat. No. 5,879,282, Fischell et al do not consider using an expandable radioactive source to reduce the edge effect that occurs with the use of a radioactive stent.